Jami` at-Tirmidhi 675
جامع الترمذي#675SahihIbn Umar narrated:"The Messenger of Allah made Sadaqatul-Fitr an obligation upon the male and female, the free and the bondsmen, as a Sa of dried dates or a Sa of barley." He said: "So the people equated that to half a Sa of wheat
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirSahih
Al-AlbaniSahih
Bashar Awad MaaroufHasan Sahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 7:59